Anyone who owns a carbon fiber tank knows how easy the clear coat can get scuffed up with unsightly dings. Bump a carbon fiber tank into anything solid and it leaves a permanent white scar or gash. If carbon fibers are exposed or frayed from a hard impact a tank won't pass hydro inspection. Any well used fireman's SCBA tank is beat up looking from being banged around. I like the posts on this forum when owners share ideas how they armor protect their fill tanks without spending an arm and a leg for over priced add ons.
Most tank protection accessories are easy to find at online dive shops at low cost or can be assembled without special skills. The only component I ordered online for my 6.8L tank was the carry strap. This is a high quality velcro carry strap for $13 from scuba.com. It has a hard rubber carry handle as seen in the photo posted below.
https://www.scuba.com/scuba-gear-225/042035/Innovative-Tank-Carrier.html
It is easy to make a wood cradle for any tank diameter. I connected the stand base using wood dowel rod cut into two 12" length spacers. Various diameter 3' dowel rod is available at home supply and craft stores. Bungee cords hold the tank to the base. If your aren't a DIY'er to make a tank base, check out CJ_86's custom tank stands in the AGN member classifieds. He can make them to fit any size carbon fiber tank for $25. I used to have a small 3L tank that I protected with a rifle sock doubled over it. A rifle sock won't stretch over a 6.8L sized tank. I found that a knit ski cap makes a perfect sized covering over a 6.8L or 9L tank. I bought a pair of knit caps for $2.40 apiece that fit over the tank ends like a glove. I added a layer of rubber ventilated shelf liner under the tank base and shoulder for extra cushioning. I removed the tank valve and cut a round hole in the front side cap then slid both caps over the padding. I hand stitched the ski caps to each other at the middle of the tank. The velcro carry strap is held on tight with zip ties.
It was easy to make and a fun indoor project during the dreary winter weather. There are lots of threads on this forum showing creative ways to protect a carbon fiber tank. This one cost only $20, adds less than a pound and looks decent.